Production of molded articles



'1 U ITED STATES PATENT OFFICE."

"THOMAS A. EDISON, OF WEST ORANGE, NEW JERSEY, ASSIGNOR TO NEW JERSEYPATENT COMPANY,-OF WEST ORAN GE, NEW JERSEY, A CORPORATION OF NEWJERSEY. 1

' PRODUCTION OF MOLDED ARTICLES.

1,377,192. Specification of Letters Patent.

No Drawing.

provements in the Production of Molded Articles, of which the followingis a, de-

' scription.

My invention relates to the production of molded articles, especiallyphonograph record blanks, and more particularly to an improved materialor composition for such molded articles, an improved binder for saidmaterial, and the processes of making such material and binder.

The principal object of the invention resides in the production of amaterial for molded articles which is of superior quality so that whenformed into a molded article under heat and pressure, it will be hard,tough, substantially non-crystalline, very .smooth and of substantiallyuniform density and texture throughout.

In carrying out my invention, I first make the binder for the materialto be molded by mixing any of a number of different resins, butpreferably ordinary pine rosin, with any of a number of different dryingoils but preferably linseed oil, and boilin the same. The mixturepreferably is ma e up of one part by weight of the resin and one part byweight of the drying oil. The drying oil is preferably partiallyoxidized, either before mixing the same with the resin or during theboiling of the mixture of resin and drying oil. In oxidizing the dryingoil before mixing with the resln, the same is boiled for a considerableperiod with an oxidizing agent such, for example, as peroxid of lead,the amount of peroxid of lead employed preferably being from 2%% to 3%by weight of the oil. One part by weight of the oxidized dryin oil isthen mixed and boiled with one part hy weight of the resin. When thedrying oil is oxidized during the boiling of the mixture of the resinand drying oil, an oxidizing agent, such as peroxid of lead, equal tofrom 5% to 6% by we'i ht of the mixture, is boiled therewith. he

resin, of course, is also partially oxidized.

In either case, the resulting product is a binder of superior quality inthe form of a Application filed January 18, 1919. Serial No. 271,899.

stiff liquid which is neither too sticky nor too brittle when hardened;

The binder produced as described above s then mixed with a fillermaterial comprising any suitable finely divided inert substance, such aschina clay, and a small quantity of fibrous material, preferably cottonflock, in a mixer which is heated to about 325 degrees F., the mixerbeing operated untll' the ingredients are thoroughly mixed. When chinaclay and cotton flock are used for the filler of my improved material, I

(find that good results are obtained by using from 20% to 25% by weightof the resin o1l compound or binder, about 3% by weight of cotton flock,and from 72% to 77% by weight of china clay.

The material is noW removed from the mixer, cooled, and then ground finein aball or pebble mill. During the grinding of the material, it issubjected to a stream of hot air in order to still further oxidize theingredients of the binder, especially the drying oil. The material issubjected to the action of the current of hot air until the properdegree of oxidation is attained. Instead of oxidizing the materialduring the grinding thereof, it may be oxidized after being ground, byremoving the same from the" grinding mill and putting it into arevolving cylinder through which hot air is forced.

After being ground, the material is ready for molding. In making diskrecord blanks, the powdered material produced by the ball or pebble millis placed in suitable molds and formed under hydraulic pressure and heatinto disks. The surfaces of the disks thus produced are very smooth andthe disks are hard and tough and of substantially uniform density, beingentirely free of hard spots such as are sometimes-present in disk recordblanks of a similar character heretofore produced.

Disk record blanks formed as described above may be covered with asuitable veneer or coating designed to be impressed with a sound recordmatrix, such as the varnish consisting of a mixture of phenol resin andhexa-methylene-tetra-amin described in Patent No. 1,098,608 toAylsworth. This varnish is preferably applied by brushing or paintingthe same onto the blank. After the varnish has dried, the sound recordis to the absence of hard spots in the blanks formed of my improvedmaterial. Moreover, such records, when reproduced, are substantiallyfreefrom scratch. This I believe is due to the fact that a blank formed ofmy improved material is substantially perfectly smooth, with none of thefibers or particles of the filler projecting from the body of the blank,with the result that when the sound record is impressed into the varnishcoating, none of the particles of the fibrous or other material of theblank will be forced through the varnish coating or any appreciabledistance thereinto so as to form irregularities in the surface of therecord grooves.

While my improved material is especially designed for use in makingsound record blanks, the same is adapted for use in making numerousother molded articles. Moreover, it is to be understood that I am notlimited to the use of the particular ingredients described in forming myimproved material, nor to the exact method described for making suchmaterial, but that my invention is subject to various changes and-modifications without departure from the spirit thereof or the scope ofthe appended c aims.

Having now described my invention, what I claim asnew and desire toprotect by Letters Patent is as follows 1. A composition adapted for useinforming molded articles, comprising a finely divided filler materialheld together by a binder comprising substantially equal parts of aresin and a drying oil, substantially as described. j

2. A composition adapted for use in forming molded articles, comprisinga mixture of finely divided material and cotton flock as a filler, heldtogether by a binder com ris ing a resin and a drying oil, substantial yas described.

3. A composition adapted for use in forming molded articles, comprisin afinely divided filler containing cotton ock held together by a bindercomprising a resin and a drying oil, substantially as described.

4. composition adapted for use in forming molded articles, comprising amixture of powdered china clay and cotton flock as a filler, heldtogether by a binder comprising a mixture of a drying oil and a resin,substantially as described.

5. The method of producing material adapted for use in making moldedarticles, which consists in mixing a resin with a drying oil with theapplication of heat, then which consists in boiling a mixture of aresin,

a drying oil and an oxidizing a ent, then mixing the resulting productwith a finely divided filler material and fibrous material with theapplication of heat, cooling the mixture, and then grinding the mixtureand subjecting the same to an oxidizing action, substantially asdescribed.

8. A sound record blank formed from a material comprising finely dividedmaterial containing cotton flock as a filler, held together by a bindercomprising a mixture of a drying oil and a resin, substantially asdescribed.

' 9. A sound record blank formed from a material comprising a mixture ofpowdered china clay and cotton flock as a filler, held together by abinder comprising a mixture of a drying oil and a. resin, substantiallyas described.

10. A sound record blank formed from a material comprising finelydivided material containing cotton flock as a filler, held together by abinder comprising a mixture of an oxidized drying oil and a resin,substantially as described.

11. A sound record blank formed from a material comprising finelydivided material containing cotton flock as a filler, held together by abinder comprising a mixture of oxidized linseed oil and a resin,substantially as described.

12. A sound record blank formed from a material comprising a mixture ofpowderedchina clay and cotton flock as a filler, held together by abinder comprising a mixture of an oxidized drying oil and a resin,substantially as described.

13. A sound record blank formed from a material comprising a mixture ofpowdered china clay and cotton flock as a filler, held together by abinder comprising a mixture of oxidized linseed oil and a resin,substantially as described. I

14. A sound record blank formed from a composition comprising a finelsubstantially as described.

15. A sound record blank formed froma composition comprising a finelydivided divided filler material held together by a binder comprising amixture of a resin and a drying oil,

filler material held together by a binder com- 17. A sound record blankformed from a prising a mixture of a resin and an oxidized composition.comprising a finely divided 10 drying oil, substantially as described.filler material held together by a binder 16. A sound record blankformed from a comprising a mixture of rosin and oxidized 5 compositioncomprising a finely divided linseed oil, substantially as described.

filler material held together by a binder com- This specification signedthis 14th day of prising a mixture of a resin and oxidized January,1919.

linseed oil, substantially as described. THOS, A. EDISON.

